Goldisthal pumped-storage plant, in Thuringia, Germany, was officially commissioned in September 2003 and is, at present, Europe's most advanced pumped-storage plant.
The pumped-storage plant is expected to reduce peak load deficits and to provide a minute reserve for losses of larger power station blocks in the Vattenfall grid. These features make a significant contribution to the safe operation of the grid.
The pump turbines, each rated at 265 MW, were supplied in a consortium, in which Voith Hydro was primarily responsible for the hydraulic design and the entire control system, including the technology of variable-speed turbine control in two of four machines.
By means of the variable-speed control, power input during pumping can be controlled continuously. Also, efficiency especially in turbine part load ranges is improved remarkably.
Start-up of the turbine is only considerably faster and provides much smoother operation for the complete unit compared to fixed-speed units.
Variable-speed is, therefore, an advantage for overall unit performance, and also for flexibility of operation within grid regulation.